Conventionally, there is provided an image reading device including a reading mechanism for allowing a light source opposed to a pickup device with an original interposed therebetween to irradiate light and detecting the intensity of light formed on the pickup device after the light transmits a light transmission original (hereinafter, referred to as a transmission original) such as a film so as to optically read an image of a transmission original.
In such an image reading device, the light source and the pickup device may be provided so as to be reciprocally moved in a sub-scanning direction and the light source and the pickup device may be independently moved using driving mechanisms. In the image reading device in which the light source and the pickup device are reciprocally moved in the sub-scan direction, the light source and the pickup device may be disconnected. In this image reading device, for example, the light source is provided on a cover member of the image reading device such that the light source and the pickup device are connected/disconnected by closing/opening the cover member when an original is set.
In the image reading device in which the light source and the pickup device can be disconnected, when the light source and the pickup device are connected again, a relative position between the light source and the pickup device in the sub-scanning direction may be shifted from a position suitable for reading the original. Accordingly, when the original is instructed to be read, the relative position between the light source and the pickup device in the sub-scanning direction is corrected before an operation for reading the original.
For example, there is a scanner device in which position display means for displaying the position of a first main body side carriage is mounted in the first main body side carriage of a conventional scanner main body, a unit side carriage driven by a motor is mounted in a transmission unit, a unit side light source and a position detection sensor are mounted in the unit side carriage, and the motor is driven by a control circuit such that the unit side carriage is moved to a position for detecting the position display means so as to conform to the position of the first main body side carriage when the position detection sensor does not detect the position display means at the same time of reading a transmission original (for example, see Patent Document 1).
Patent Document 1: Japanese Unexamined Application Patent Publication No. Hei7-231378
However, the above-described conventional technology, since the light source and the pickup device are independently moved using the driving mechanisms, the relative position between the light source and the pickup device in the sub-scanning direction may be sifted and reading precision may be deteriorated. In addition, in the above-described conventional technology, since the light source and the pickup device are independently moved using the driving mechanisms, the image reading device becomes large-sized and power consumption is increased.
In the technology disclosed in Patent Document 1, in order to adjust the relative position between the light source and the pickup device in the sub-scanning direction, it is necessary to mount the position detection sensor in the unit side carriage. Thus, the manufacturing cost of the device is increased.